Coated particles and pharmaceutical dosage forms

ABSTRACT

The present invention relates to coated particles and pharmaceutical dosage forms comprising the active substances sensitive to environmental influences. The coating of the present invention provides stability and protection of the active substance to environmental influences and in particular from oxidation and/or environmental humidity by coating.

This application is a continuation of application Ser. No. 10/544,920,filed Nov. 4, 2005 now abandoned, which is a 371 National Phase Entry ofPCT Application PCT/SI04/00009, filed Feb. 11, 2004, which in turnclaims priority to Slovenian patent application P-200300041, filed Feb.12, 2003.

FIELD OF THE INVENTION

The present invention relates to the field of pharmaceutical industry,more specifically to coated particles and pharmaceutical dosage formscomprising the active substances sensitive to environmental influences.

The coated particles of the present invention are the particles of theactive substance or the particles of the active substance and one ormore pharmaceutical excipients in the form of particles of regular orirregular shapes, such as microcapsules, microspheres, granules, pelletsand the like said particles are protected from environmental influencesand in particular from oxidation and/or environmental humidity bycoating. Said particles are embedded either in an uncoatedpharmaceutical dosage form or in a coated pharmaceutical dosage formwherein the coating of the present invention affords protection andconsequently stability of the active substance and one or morepharmaceutical excipients from environmental influences and inparticular from oxidation and/or environmental humidity. When coatedparticles are embedded in a coated pharmaceutical dosage form saidcoating could be also any other in the prior art known coating.

The pharmaceutical dosage forms of the present invention are theuncoated or coated pharmaceutical dosage forms.

The uncoated pharmaceutical dosage forms of the present inventioncomprise the coated particles of the present invention and one or morepharmaceutical excipients wherein the coating of such particles affordsprotection of the active substance and one or more pharmaceuticalexcipients from environmental influences and in particular fromoxidation and/or environmental humidity.

The coated pharmaceutical dosage forms of the present invention comprisecoated particles of the present invention and/or uncoated particles ofthe active substance or of the active substance and one or morepharmaceutical excipients and the coating which affords protection ofthe active substance and one or more pharmaceutical excepients fromenvironmental influences and in particular from oxidation and/orenvironmental humidity. When coated particles are embedded in a coatedpharmaceutical dosage form said coating could be also any other in theprior art known coating.

The coated particles and the pharmaceutical dosage forms of the presentinvention are stable to the influences of the environment, that is,afford stability of the active substance, which is sensitive toenvironmental influences, and one or more pharmaceutical excipients toenvironmental influences by protecting the active substance and one ormore pharmaceutical excipients from environmental influences and inparticular from oxidation and/or environmental humidity.

The present invention also relates to the coated particles and thepharmaceutical dosage forms comprising the active substance which isHMG-CoA reductase inhibitor.

The present invention also relates to the methods and the processes forthe preparation of the coated particles and the pharmaceutical dosageforms of the present invention.

The present invention further relates to the use of the active substancefor the preparation of the coated particles and/or pharmaceutical dosageforms of said invention for the treatment and to the methods oftreatment for a variety of diseases by administering the coatedparticles and/or pharmaceutical dosage forms of the present inventionwherein the diseases are selected from the group consisting ofdyslipidemia, hyperlipidemia, hypercholesterolemia, atherosclerosis,arteriosclerosis, cardiovascular disease, coronary arterial disease,coronary heart disease, vascular disorders, inflammatory disease,allergic disease, neurodegenerative disease, cancer disease, viraldisease (WO 0158443), abnormal bone states, (WO 0137876),amyloid-(precursor protein processing disorders such as Alzheimer'sdisease or Down's Syndrome (WO 0132161).

BACKGROUND OF THE INVENTION

Many therapeutic substances are sensitive to environmental influencesand due to these impacts their active forms are transformed todegradation products which are often less effective than the activeforms. Apart from lower efficacy, degradation products may also causeundesirable effects thus affecting safe use of a medicament. Already avery low percent of impurities or degradation products of the activesubstance may significantly impair a drug safety. Therefore, it isimportant that therapeutic substance is as pure as possible whenadministered, that is, the percent of degradation products andimpurities should be minimal.

Procedures for the preparation of an active substance per se (e.g.,processes of isolation and purification), and interim phases of storageof the active substance and/or its intermediates during the productionand the phases of storage of the active substance up to the procedureand during the course of pharmaceutical dosage form production have aninfluence on the percent of impurities and degradation products of theactive substance. At the same time, pharmaceutical excipients comprisedin the pharmaceutical dosage form have an influence on the percent ofdegradation products and impurities in the active substance. Saidpharmaceutical excipients are selected from the group consisting offillers or diluents, binders, lubricants, glidants, disintegrants,colorants, flavors, adsorbents, plasticizers and the like.

Not only an active substance undergoes degradation by environmentalinfluences but also excipients in a pharmaceutical dosage form may bedegraded. Degradation products of the latter act as the reactive siteswhich trigger degradation reactions of the active substance in apharmaceutical dosage form.

Among the environmental factors which have an impact on an activesubstance are, for example, temperature, humidity, light, (e.g. UVlight) and gases, present in the environment such as, e.g., oxygen orcarbon dioxide. An important factor is also the pH environment, that is,presence of substances which have influence on acidity or alkalinity ofthe environment (e.g., acids, alkalis, salts, metal oxides) and thereactivity of the ambient medium or active substance (free radicals,heavy metals), etc.

The majority of therapeutic active substances are sensitive totemperature, in particular high temperature. Temperature increaseaccelerates chemical reactions and thus more degradation products areformed in a shorter period of time. In certain cases at elevatedtemperature the reactions take place which would not at normaltemperature. Thus, the temperature has an impact on the kinetic andthermodynamic parameters of the chemical reactions leading to occurrenceof degradation products.

Many active substances are sensitive to humidity. At increased humiditywater is bound to the active substance itself and/or pharmaceuticalexcipients surrounding the active substance. Water associated with oneor more other environmental influences may thus triggers degradationreactions of the active substance. For example, substances known in theprior art to be sensitive to humidity are:

-   -   β-lactamase inhibitor potassium clavulanate (Finn, M. J. et        al, J. Chem. soc. Perkin. Trans 1, 1984, 1345-349; Haginaka J.        et al, Chem. Pharm. Bull. 29, 1981, 3334-3341; Haginaka J. et        al, Chem. Pharm. Bull. 33, 1985, 218-224);        -   proton pump inhibitors such as, e.g. omeprazole,            lansoprazole and pantoprazole (Kristi, A. et al, Drug. Dev.            Ind. Pharm. 26 (7), 2000, 781-783; Ekpe, A. et al, Drug.            Dev. Ind. Pharm. 25 (9), 1999, 1057-065);        -   HGM-CoA reductase inhibitors, e.g. pravastatin and            atorvastatin.

Compounds containing structural elements which at low pH are convertedto a lactone form are generally sensitive to an acidic environment.Among them the best known are HGM-CoA reductase inhibitors (statins) andrelated compounds which comprise 7-substituted-3,5-dihydroxyheptanoicand/or 7-substituted-3,5-dihydroxyheptenoic acid groups. Apart fromconversion to a lactone form, other mechanisms of degradation of saidactive substances may take place in an acidic environment, for example,isomerization in case of pravastatin (Serrajuddin, A. T. M. et al,Biopharm. Sci. 80, 830-834, 1991; Kearney, A. S. et al, Pharm. Res. 10,1993, 1461-1465).

Statins and related compounds are in the form of a cyclic ester—lactone,therefore, among others they are also sensitive to an alkaline medium,where they are transformed to an acid form.

Compounds in the environment which increase acidity or alkalinity of theenvironment trigger degradation reactions of an active substancesensitive to acidic or alkaline environment. Carbon dioxide in thepresence of humidity or water, in which it is freely soluble, formscarbonic acid which increases the acidity of the environment.

Light and in particular UV light induces degradation reactions of activesubstances, especially organic ones. It is known that among otherslevofloxacin (Sato, Y. Y. E. and Moroi, R., Arzneim, Forsch./Drug Res.43, 1993, 601-606) and atorvastatin are also sensitive to light (Hurley,T. R. et al, Tetrahedron 49, 1993, 1979-1984).

Oxygen induces oxidation, that is, oxidative degradation reactions of anactive substance and/or pharmaceutical excipients resulting in formationof the reactive sites and/or degradation products which lead to furtheroxidation or further oxidative degradation reactions of the activesubstance and/or pharmaceutical excipients. For example, activesubstances known in the prior art to be sensitive to oxidation are:

-   -   Captopril, chlorpomazine, morphine, L-ascorbic acids vitamin E,        phenylbutazone and tetracyclines (Waterman, K. C., et al, in        “Stabilization of Pharmaceuticals to Oxidative Degradation”,        Pharmaceutical Development and Technology, 7(1), 2002, 1-32);    -   Omeprazole; and    -   HGM-CoA reductase inhibitors, e.g. pravastatin, atorvastatin,        simvastatin and lovastatin (Javernik, S., et al, Pharmazie 56,        2001, 738-740; Smith, G. B., et al, Tetrahedron 49, 1993,        44474462; patent application P-200200244).

HMG-CoA reductase inhibitors (statins) are also among the activesubstances sensitive to pH of the environment, humidity, light,temperature, carbon dioxide and oxygen. They are known as the mosteffective therapeutically active substances for the treatment ofdyslipidemias and cardiovascular disease, selected from the groupconsisting of dyslipidemia, hyperlipidemia, hypercholesterolemia,atherosclerosis, arteriosclerosis, coronary artery diseases, coronaryheart disease and the like, associated with the metabolism of lipids andcholesterol. The mechanism of action of statins is the inhibition of thebiosynthesis of cholesterol and other sterols in the liver of humans oranimals. They are competitive inhibitors of HMG-CoA reductase or3-hydroxy-3-methyl-glutaryl-coenzyme A reductase, an enzyme whichcatalyses the conversion of HMG-CoA to mevalonate in the liver of humansor animals, which is an important step in the biosynthesis ofcholesterol in the liver. Recent studies indicate that, in addition tothe said therapeutic effects, statins also have other therapeuticeffects and thus they are useful for the treatment of diseases, abnormalconditions and disorders which are selected from the group consisting ofvascular disorders, inflammatory disease, allergic disease,neurodegenerative disease, malignant disease, viral disease (WO0158443), abnormal bone states, (WO 0137876), amyloid-β precursorprotein processing disorders such as Alzheimer's disease or Down'sSyndrome (WO 0132161).

Among the statins, for example, the following are known: pravastatin,atorvastatin simvastatin, lovastatin, mevastatin or compactin,fluvastatin or fluindostatin, cer(i)vastatin or rivastatin, rosuvastatinor visastatin, and itavastatin or pitavastatin, or nisvastatin.

Pravastatin is chemically (betaR*,deltaR,1S,2S,6S,8S,8aR)-1,2,6,8,8a-hexahydro-beta, delta,6-trihydroxy-2-methyl-8-((2S)-2-methyl-1-oxobutoxy)-1-naphthaleneheptanoic acid. A sodium salt of said acid is sodium pravastatin. It wasdescribed first time in U.S. Pat. No. 4,346,227.

Atorvastatin is chemically a (R—(R*,R*))-2-(4-fluorophenyl-beta,delta-dihydroxy-5-(1-methylethyl)-3-phenyl-4-((phenylamino)carbonyl)-1H-pyrrole-1-heptanoicacid hemicalcium salt. It was described first time in U.S. Pat. No.5,273,995.

Rosuvastatin is chemically (2:1)(3R,5S,6E)-7-(4-(4-fluorophenyl)-6-(1-methylethyl)-2-(methyl(methylsulfonyl)amino)-5-pyrimidinyl)-3,5-dihydroxy-6-heptenoicacid calcium salt. It was described first time in U.S. Pat. No.5,260,440.

Fluvastatin is chemicallyR*,S*-(E)-(+−)-7-(3-(4-fluorophenyl)-1-(1-methylethyl)-1H-indol-2-yl)-3,5-dihydroxy-6-heptenoicacid. Fluvastatin sodium is a sodium salt of said acid. It was describedfirst time in European patent 114027.

Simvastatin is chemically (1S-(1alpha, 3alpha, 7beta, 8beta (2S*, 4S*)8abeta))-1,2,3,7,8,8a-hexahydro-3,7-dimethyl-8-(2-(tetrahydro-4-hydroxy-6-oxo-2H-pyran-2-yl)ethyl)-1-naphthalenyl-2,2-dimethylbutanoate.It was described first time in U.S. Pat. No. 4,444,784.

Lovastatin is chemically (1S-(1alpha, 3alpha, 7beta, 8beta (2S*, 4S*) 8abeta))-1,2,3,7,8,8a-hexahydro-3,7-dimethyl-8-(2-(tetrahydro-4-hydroxy-6-oxo-2H-pyran-2-yl)ethyl)-1-naphthalenyl-2-methylbutanoate.It was described first time in U.S. Pat. No. 4,231,938 and JP 8425599.

Itavastatin is chemically(S—(R*,S*-(E)))-7-(2-cyclopropyl-4-(4-fluorophenyl)-3-quinolynyl)-3,5-dihydroxy-6-heptenoicacid. Pitavastatin is a lactone form of itavastatin. They were describedfirst time in European patent no. 304063 and U.S. Pat. No. 5,011,930,respectively.

Mevastatin is chemically(3R,5R)-3,5-dihydroxy-7-((1S,2S,6S,8S,8aR)-2-methyl-8-((2S)-2-methylbutanoyl)oxy)-1,2,6,7,8,8a-hexahydronaphthalen-1-yl)heptanoicacid. It was described first time U.S. Pat. No. 3,983,140.

Cerivastatin is chemically(S—(R*,S*-(E)))-7-(4-(4-fluorophenyl)-5-(methoxymethyl)-2,6-bis(1-methylethyl)-3-pyridinyl)-3,5-dihydroxy-6-heptanoicacid. It was described first time in European patent no. 491226.

Many of the above statins are sensitive in particular to environmentalinfluences, for example, atmospheric influences and pH of theenvironment. In the prior art it is known that certain statins aresensitive to acidic environment (low pH values) wherein they aredegraded to their lactone forms and different isomers. For example,pravastatin, atorvastatin, itavastatin, and fluvastatin are converted totheir lactone forms in an acidic environment.

In the prior art it is also known that statins which are in the lactoneform, e.g. lovastatin and simvastatin, are sensitive to alkalineenvironment wherein they are converted to the acid form.

The sensitivity of different pharmaceutical active substances tooxidative degradation is described by Waterman, K. C., et al, in“Stabilization of Pharmaceuticals to Oxidative Degradation”,Pharmaceutical Development and Technology, 7(1), 2002, 1-32, andpossible approaches to stabilize pharmaceutical active substancesagainst oxidative degradation are also presented. The above mentionedarticle suggests that study of oxidative mechanism in solidpharmaceutical dosage forms is difficult and demanding as indicated byfew reports in said area. An active substance per se and more frequentlyan active substance in a pharmaceutical dosage form may oxidize. Duringthe processing of drug to form a solid dosage form, it is possible tomechanically generate amorphous drug. The percent of formed amorphousform is usually small and below 1%. Amorphous drug regions have greatermobility and lack crystal-lattice stabilization energy, and as a resultoxygen permeability and solubility will be higher. Greater mobility andhigher oxygen concentration present in amorphous active substance alsofacilitate electron transfer to oxygen. (Waterman, K. C., et al,Stabilization of Pharmaceuticals to Oxidative Degradation,Pharmaceutical Development and Technology, 7(1), 2002, 1-32).

Byrn, S. R., et al. (Solid-State Chemistry of Drugs, 2^(nd) Ed., SSCI,West Lafayette, 1999) disclose that molecular oxygen from atmospherereacts with organic crystals and said reactivity depends on a crystalform and morphology, respectively, which determines permeability tooxygen and its solubility in the crystal lattice. In some examples thereactivity decreases with increased melting point indicating that highercrystalline lattice energy inhibits diffusion of oxygen.

It is in general more difficult to remove an electron from a drug whenit is more positively charged. Therefore drug stability againstoxidation is often greater under lower pH conditions. The sensitivity ofan active substance to oxidation also depends on a pharmaceutical dosageform per se and pharmaceutical excipients in it. Pharmaceuticalexcipients also influence oxidation of the active substance in apharmaceutical dosage form. They can potentially solvate some of theactive substances either directly or by bringing in low levels ofmoisture. In a solid solution form, the active substance will beamorphous with all the corresponding reactivity discussed above.Excipients themselves can be a source of oxidants or metals (e.g.present impurities) and may be involved in occurrence of mobileoxidative species, such as peroxyl radicals, superoxide and hydroxylradicals. This depends on the hydrogen bond strength of the excipientand whether there are good electron donor sites (e.g. amines). Peroxideimpurities are often present in polymeric excipients and they are amajor source of oxidation in pharmaceutical formulations. (Waterman, K.C., et al, Stabilization of Pharmaceuticals to Oxidative Degradation,Pharmaceutical Development and Technology, 7(1), 2002, 1-32).

In the studies we have found that some of the above statins areparticularly sensitive to oxidation. Among them particularly sensitiveare certain polymorphic or amorphous forms of atorvastatin, pravastatin,lovastatin, simvastatin and rosuvastatin.

The influence of oxygen on occurrence of degradation products ofamorphous and four polymorphic forms of atorvastatin was investigated.The samples of amorphous atorvastatin and polymorphic forms I to IV ofatorvastatin were exposed at 80° C. in normal (air) and oxygenatmosphere for 3 days. The assay of oxidation products was determined byliquid chromatography. All of the chosen forms of atorvastatin stored at4° C. were analyzed as the reference samples.

TABLE 1 Increase of the degradation products of amorphous and differentcrystalline forms of atorvastatin stored at 80° C. in normal (air) andoxygen atmosphere for 3 days in respect to reference samples Increase ofAmor- degradation phous Crystalline Crystalline Crystalline Crystallineproducts % ATV form I form II form III form IV AIR 1.04 0.04 0.25 0.111.14 OXYGEN 3.4 0.07 0.71 0.47 3.67

The above study shows that different forms of atorvastatin are variablysensitive to the impact of oxygen regarding the formation of degradationproducts. In case of amorphous atorvastatin and crystalline form IV thepercent of oxidation degradation products essentially increased inoxygen atmosphere and normal atmosphere (air). In case of crystallineforms I, II and III the percent of oxidation degradation products waslow in air atmosphere, while in oxygen atmosphere the percent ofoxidation degradation products increased in crystalline forms II andIII.

We can conclude that crystalline form I is stable to oxygen andoxidation, crystalline forms II and III are slightly sensitive tooxidation and crystalline form IV and amorphous atorvastatin are highlysensitive to oxidation.

PRIOR ART

The patent documents which solve the problem of maintaining thestability of some of the listed statins at low pH environment are:

-   -   for atorvastatin with alkaline compounds U.S. Pat. No.        5,686,104, U.S. Pat. No. 6,126,971, WO 9416693 and European        patent no. 680320, and with alkaline and/or buffering compounds        WO 02072073;    -   for pravastatin with alkaline compounds European patent no.        336298, U.S. Pat. No. 5,030,447 and U.S. Pat. No. 5,180,589,        with alkaline and/or buffering compounds and other excipients WO        02076376, with buffering compounds WO 03000239 and WO 03000177;    -   for fluvastatin with alkaline medium European patent no. 547000        and U.S. Pat. No. 5,356,896;    -   for itavastatin with alkaline compound WO 9723200 European        patent no. 814782;    -   for atorvastatin, pravastatin and other statins with polymers        which contain amino groups or amido groups, WO 0176566 and U.S.        Pat. No. 20020035142;    -   for atorvastatin, pravastatin, fluvastatin, cerivastatin,        mevastatin, pitavastatin, rosuvastatin, lovastatin and        simvastatin with amino sugars WO 02089788;    -   for atorvastatin, pravastatin, fluvastatin and cerivastatin with        buffering compounds WO 0035425;    -   for atorvastatin, pravastatin, fluvastatin and cerivastatin with        alkaline and/or buffering compound WO 0193860.

Among the patent documents which solve the problem of maintaining thestability of some of the listed statins at high humidity and temperatureis WO 9949896 which discloses stabilization of pravastatin withbeta-cyclodextrin.

A review of the known methods (antioxidants, packaging) forstabilization of the active substance from oxidation is presented, e.g.,in Waterman, K. C., et al, Pharm. Dev. and Technol. 7, 2002, 1-32.

For the prevention or reduction of active substances oxidation in apharmaceutical dosage form, different approaches are used for example:

-   -   increase of the concentration of the active substance in a        pharmaceutical dosage form when oxidation is caused by peroxide        and metallic impurities in pharmaceutical excipients;    -   addition of chelating agents (such as, e.g. citric acid, EDTA,        fumaric and malic acid) to the formulation for mitigation of        metallic impurities;    -   use of high-purity pharmaceutical excipients;    -   use of alternative excipients or decrease their amount in the        pharmaceutical dosage form, especially when peroxide impurities        are the cause of oxidation;    -   use of antioxidants which can reduce formation of peroxides, but        maybe less effective at eliminating peroxides already present in        a dosage form.

For individual active substances there is no general way to predictoptimal solution for oxidation prevention and the publications availableare scarce (Waterman, K. C., et al, Stabilization of Pharmaceuticals toOxidative Degradation, Pharmaceutical Development and Technology, 7(1),2002, 1-32).

Among suitable antioxidants there are described:

-   -   chain terminators (e.g. thiols and phenols);    -   sacrificial reductants which are oxidized more readily than the        active substance and thus remove present oxygen (e.g. sulfites        and ascorbic acid) wherein their combination may act        synergistically (e.g. a combination of ascorbic palmitate and        tocopherol);    -   peroxide quenchers (e.g. Fe²⁺) which degrade peroxides by        Fentonprocess. Their use is limited because in this process a        free hydroxyl radical is formed.    -   cyclodextrins which cover the site of an active substance,        subjected to oxidation (Waterman, K. C., et al, Stabilization of        Pharmaceuticals to Oxidative Degradation, Pharmaceutical        Development and Technology, 7(1), 2002, 1-32).

In addition to above-mentioned solutions, prevention from oxidation canbe achieved by packaging where the oxygen content in a space surroundingan active substance and permeability of oxygen through the package wallsand cap are regulated. It is possible to reduce the oxygen contentcontained in the package by packaging under nitrogen atmosphere. Whendrugs are concerned, a blister is the most suitable form of packagingunder controlled atmosphere. Blisters which are less permeable orimpermeable to oxygen (e.g. foil-foil) are usually more expensive.Despite the numerous different described methods of stabilization indifferent ways, for example, with the addition of antioxidants to apharmaceutical dosage forms by packaging a pharmaceutical formulationinto a suitable package, these solutions have not shown to be convenientfor all active substances and all markets, respectively (Waterman, K.C., et al, Stabilization of Pharmaceuticals to Oxidative Degradation,Pharmaceutical Development and Technology, 7(1), 2002, 1-32).

Different types of packaging materials for the protection ofpharmaceutical active substances and pharmaceutical formulation fromoxidation are disclosed in numerous patents.

WO 0076879 discloses the barrier pack comprising a cover portion bondedto a base portion to form a sealed unit package wherein the coverportion comprises at least one cavity containing a product, and thecover portion and/or base portion has an absorbing agent material(desiccant).

European patent no. 370755 discloses a packaging material for drugswhich is specially designed with the foil comprising an innerpolypropylene film, an intermediate olefin film and an outerpolypropylene film. Further said package may also comprise aluminiumfoil.

European patent no. 595800 discloses a packaging material comprising alayer which removes oxygen from a package by means of an enzymereaction; the package has an outer film which is impermeable to gas andwater vapours (e.g. a laminate such as polyamide and polyethylene), aninner film which is permeable to gas and impermeable to liquid (e.g.polyethylene and copolymers thereof), and intermediate film whichremoves oxygen and comprises a liquid phase with an enzyme for oxygenremoval (oxidase such as glucose oxidase) wherein an insoluble filler issuspended in a liquid phase.

The methods of coating the substances or products sensitive to oxidationwith coatings which protect said substances or products from oxidationare known in the prior art in the food industry. The coatings from milkproteins are described which also comprise carboxymethylcellulose toprevent oxidative browning of apples and potatoes (Le Tien, C., et al,Protein Coatings Prevent Oxidative Browning of Apples and Potatoes,Journal of Food Science Vol. 66, No. 4, 2001, 512-516).

In the field of pharmacy the use of ethylcellulose for coating ofascorbic acid granules for protection against oxidation is known (Wade,A., et al, Handbook of Pharmaceutical Excipients, 2nd Ed, AmericanPharmaceutical Association, Washington, and The Pharmaceutical Press,London, 1994, 186-190).

Sensitivity of lovastatin to oxidation and its stabilisation andprotection from oxidation with natural antioxidants are described byJavernik, S., et al, in Pharmazie 56(9), September 2001, 738-740.

Sensitivities of lovastatin and simvastatin and other substances (e.g.alkaline substances with pKa from 1 to 10 and from 5 to 9, respectively,which further have redox potential of about 1300 mV and about 1000 mV,respectively) to oxidation are disclosed in U.S. Pat. No. 20020132359and European patent no. 1241110 which solve the problem of oxidation bya special package form where each unit dose comprising oxygen-sensitivedrug, is individually encapsulated in the pharmaceutical packagingconstruction such that when one unit dose is dispensed the other unitdoses remained encapsulated. An oxygen-absorber is also incorporatedinto the construction. Oxygen absorber is selected from the groupconsisting of absorbents which are activated themselves or by moisture(e.g. copper powder, zinc powder), UV rays, electron ray, irradiation,microwaves or a combination thereof.

Prevention of oxidation of atorvastatin by means of suitable packaging(in the nitrogen atmosphere) is also disclosed in the patent applicationP-200200244.

In the patent documents and other prior art documents no documents havebeen found relating to different modes of solving the problem ofprotection of pharmaceutical active substances and pharmaceutical dosageform from oxidation.

Therefore, the object of the present invention is to protect andconsequently stabilize the active substance, sensitive to environmentalinfluences, and to stabilize the pharmaceutical dosage form comprisingsaid active substance and one or more pharmaceutical excipients.Further, the object of the present invention is to protect andconsequently stabilize the active substance which is sensitive tooxidation and environmental humidity, and to stabilize thepharmaceutical dosage form comprising said active substance and one ormore pharmaceutical excipients. Preferably, the object of the presentinvention is to protect and consequently stabilize the active substance,which is statin, to environmental influences and preferably to oxidationby preventing the contact between the active substance and oxygen thuspreventing occurrence of degradation products of the active substanceand preferably oxidative degradation products as well as degradationproducts of the pharmaceutical excipients.

DESCRIPTION OF THE INVENTION

The first object of the present invention is a coating which affordsprotection and consequently stability of an active substance and one ormore pharmaceutical excipients and/or pharmaceutical dosage form fromenvironmental influences and in particular from oxidation and/orenvironmental humidity.

In the context of the present invention the term coating of the presentinvention means a layer of material applied directly onto the core whichis either an active substance itself or an active substance with one ormore pharmaceutical excipients in the form of particles of regular orirregular shapes such as microcapsules, microspheres, granules, pelletsand the like, or a pharmaceutical dosage form selected from the groupconsisting of tablets, capsules or similar forms known in the prior art.Said coating affords protection of the active substance and one or morepharmaceutical excipients, respectively, from environmental influencesand in particular from oxidation and/or environmental humidity.Additionally, the coating of the present invention enables release ofthe active substance in all parts of gastrointestinal tract, regardlessof environmental pH value.

The active substance of the present invention is an active substancewhich is sensitive to environmental influences and is selected from thegroup consisting of HMG-CoA reductase inhibitor, captopril,chlorpromazine, morphine, L-ascorbic acid, vitamin E, phenylbutazone,tetracyclines and omeprazole. Preferably an active substance of thepresent invention, sensitive to oxidation and environmental humidity isa HMG-CoA reductase inhibitor selected from the group consisting ofpravastatin, atorvastatin, rosuvastatin, itavastatin, simvastatin andlovastatin.

In the context of the present invention the coating is a layer ofmaterial comprising one or more film-formers. A suitable film-former isany film-former which applied in the form of a coating onto the particleor the core of the pharmaceutical dosage form comprising the activesubstance which is sensitive to environment influences, affordsprotection of the active substance from environmental influences andpreferably against oxidation and/or environmental humidity. Mostpreferably such film-former is any film-former which affords protectionof the active substance from oxidation. Said film-former is selectedfrom the group consisting of polyvinyl alcohol (PVA) and derivatives ofcellulose. Among the derivatives of cellulose a film-former ispreferably sodium carboxymethylcellulose (NaCMC) or hydroxyethylcellulose (HEC) and most preferably sodium carboxymethylcellulose(NaCMC). A film-former may be also a combination of one or more saidfilm-formers in all possible ratios. A film former is added inconcentrations 40-100%, preferably in concentrations 60-95%, morepreferably in concentrations 70-90% to the amount of solids in acoating.

Among film-forming polymers with desired properties sodiumcarboxymethylcellulose (NaCMC) exhibits especially low permeability tooxygen if the thickness of NaCMC coating is sufficient. On the otherhand, NaCMC coating swells in contact with liquid water and forms aninsoluble gel-like film with extremely low permeability to water. Thiscould prevent the tablet disintegration and the release of the activesubstance. In addition, NaCMC gel becomes very viscous and the polymerchains cross-link through lactonization between carboxylic acid and freehydroxyl groups in the acidic gastric environment. Both of thesemechanisms could prevent the permeation of water through the coating tothe tablet core and therefore prevent release of the active substance.

It was surprisingly found that with addition of suitable excipients,selected from the group consisting of buffering agents, alkalizingagents and surface active agents the above weaknesses of NaCMC coatingare overcome.

The buffering component of the coating of the present invention is asalt of weak acid and strong base or a salt of strong acid and weak baseor other similar substance which maintains the pH within the determinedrange. The buffering component may be selected from the group consistingof:

-   a) alkali metal salts, alkali-earth metal salts and ammonium salts    of citric acid, ascorbic acid, maleic acid, sorbic acid, succinic    acid, benzoic acid, phosphoric acid, carbonic acid, sulfuric acid,    nitric acid, boric acid and silicic acid;-   b) amines in combination with a strong or weak acid, such as    trometamine (TRIS), EDTA;-   c) ion exchangers; and-   d) any combinations thereof.

Buffering components are added in concentrations 0-20%, preferably inconcentrations 0-10% to the amount of solids in the coating.

The alkalizing component of the coating of the present invention isselected from the group consisting of organic or inorganic compoundswhich contain the groups having alkaline action and may be selected fromthe group consisting of:

-   a) oxides and hydroxides of alkaline and/or alkali-earth metals,    oxides of the 4, 5 and/or 6 group of the periodic system such as    MgO, MgOH, NaOH, Ca(OH)₂;-   b) amines, such as trometamine (TRIS)), ethanolamine,    diethanolamine, triethanolamine, N-methyl-glucamine, glucosamine,    ethylenediamine, diethylamine, triethylamine, isopropylamine,    diisopropylamine;-   c) alkali amino acids, such as arginine, histidine and lysine.

Alkalizing components are added in concentrations 0-20%, preferably Inconcentrations 0-10% to the amount of solids in the coating.

The surfactant of the coating of the present invention may be selectedfrom the group consisting of ionic surfactants such as sodium laurylsulfate, nonionic surfactants such as different types of poloxamers suchas polyoxyethylene and polyoxypropylene copolymers, natural andsynthetic lecithins and esters of sorbitan and fatty acids such as Span®(Atlas Chemie), polyoxyethylenesorbitan and fatty acid esters such aspolyoxyethylene sorbitan monooleate such as Polysorbate 80 or Tween®(Atlas Chemie), polyoxyethylated hydrogenated castor oil such asCremophor® (BASF), polyoxyethylene stearates such as Myrj® (AtlasChemie) or cationic surfactants such as cetylpyridine chloride or any ofcombinations of said surfactants. Surfactants are added inconcentrations 0-20%, preferably in concentrations 0-10%, morepreferably in concentrations 0-5% to the amount of solids in thecoating.

In the context of the present invention the coating may further compriseone or more pharmaceutically acceptable pharmaceutical excipients whichare selected from the group consisting of one or more plasticizers, oneor more viscosity-increasing agents of a coating dispersion, one or morefillers, one or more lubricants or glidants, one or more colorants, andadditional pharmaceutical excipients which are used in the prior art forcoatings.

The plasticizer of the coating of the present invention may be selectedfrom the group consisting of glycerol, diglycerol, ethanolamines,ethylene glycol, polyethylene glycols, glycerol α-monomethyl ether,glycerol monochloridine, 2,3-butylene glycol, 1,2,6-hexanetriol,2-nitro-2-methyl-1,3-propandiol, propylene glycol, glyceryl triaccetate,polyoxyethylenelpolyoxypropylene copolymers, triethyl citrate, oleicacid, fractionated coconut oil and any combinations thereof. Theplasticizer is added in concentrations 1-50%, preferably inconcentrations 5-40%, more preferably in concentrations 10-30% to theamount of the film-former in the coating.

The viscosity-increasing agent of the coating dispersion of the presentinvention may be selected from the group consisting ofcarboxymethylcellulose, hydroxypropyl methylcellulose, hydroxypropylcellulose, xanthan, alginates, chitosan and any combinations thereof.The viscosity-increasing agents are added in concentrations 0-50%,preferably in concentrations 0-20% to the amount of solids in thecoating.

The filler of the coating of the present invention may be selected fromthe group consisting of lactose, polydextrose, maltodextrin, mannitol,starch and any combinations thereof. Fillers are added in concentrations0-15%, preferably in concentrations 0-5% to the amount of solids in thecoating.

The lubricant or glidant of the coating of the present invention may beselected from the group consisting of talc, magnesium stearate,colloidal silicon dioxide, stearic acid, calcium stearate and anycombinations thereof. The lubricants or glidants are added inconcentrations 0-40%, preferably in concentrations 0-25% to the amountof solids in the coating.

The colorant of the coating of the present invention may be selectedfrom the group consisting of aluminium lakes, insoluble pigments,water-soluble dyes, titanium di-oxide, talc, and any combinationsthereof. The colorants are added in concentrations 0-20%, preferably inconcentrations 0-10% to the amount of solids in the coating.

Other pharmaceutical excipients of the coating of the present inventionare the substances used in this field of art for coatings and are knownin the prior art.

A solvent of the coating dispersion may be water, different combinationsof organic solvents or combinations of organic solvents and water.

The thickness of the coating of the present invention applied directlyonto the core which is either an active substance itself or an activesubstance with one or more excipients in the form of particles ofregular or irregular shapes such as microcapsules, microspheres,granules, pellets and the like, or a pharmaceutical dosage form selectedfrom the group consisting of tablets, capsules or similar forms known inthe prior art should be sufficient to achieve its functionality, thismeans impermeability to oxygen and/or water. The thickness of thecoating is in the range 5-200 μm, preferably 5-100 μm.

The amount of the coating applied can be estimated from the followingequation:

$w = \frac{{dS}_{core}\rho_{c}}{m_{core}}$w weight of coating in respect to core massd thickness of coatingS_(core) surface area of the coreρ_(c) density of the coatingm_(core) mass of the core

Further object of the present invention are the coated particles whichare particles of the active substance or the particles of the activesubstance and one or more pharmaceutical excipients in the form ofparticles of regular or irregular shapes, such as microcapsules,microspheres, granules, pellets and the like said particles areprotected from environmental influences and in particular from oxidationand/or environmental humidity by coating. Said particles are embeddedeither in an uncoated pharmaceutical dosage form or in a coatedpharmaceutical dosage form wherein the coating of the present inventionaffords protection and consequently stability of the active substanceand one or more pharmaceutical excipients from environmental influencesand in particular from oxidation and/or environmental humidity. Whencoated particles are embedded in a coated pharmaceutical dosage formsaid coating could be also any other in the prior art known coating.

The coated particles of the present invention comprise (a) an activesubstance or an active substance and one or more pharmaceuticalexcipients wherein the active substance is sensitive to environmentalinfluences and (b) the coating of the present invention which affordsprotection of the active substance and one or more pharmaceuticalexcipients from environmental influences.

The coated particles of the present invention comprise (a) an activesubstance or an active substance and one or more pharmaceuticalexcipients wherein the active substance is sensitive to oxidation andenvironmental humidity and (b) the coating of the present inventionwhich affords protection of the active substance and pharmaceuticalexcipients from oxidation and/or environmental humidity.

The coated particles of the present invention comprise (a) an activesubstance or an active substance and one or more pharmaceuticalexcipients wherein the active substance is sensitive to oxidation and(b) the coating of the present invention which affords protection of theactive substance and pharmaceutical excipients from oxidation.

The active substance of the present invention embedded in the coatedparticles of the present invention is selected from the group consistingof HMG-CoA reductase inhibitor, captopril, chlorpromazine, morphine,L-ascorbic acid, vitamin E, phenylbutazone tetracyclines and omeprazole.Preferably an active substance of the present invention, is an HMG-CoAreductase inhibitor selected from the group consisting of pravastatin,atorvastatin, rosuvastatin, itavastatin, simvastatin and lovastatin.

The pharmaceutical dosage forms of the present invention are the coatedor uncoated pharmaceutical dosage forms.

Further object of the present invention is the coated pharmaceuticaldosage form which comprises:

-   a) a mixture of one or more coated particles of the present    invention and/or one or more uncoated particles containing one or    more active substances of the present invention which are sensitive    to environmental influences, preferably to oxidation and    environmental humidity and most preferably to oxidation;-   b) one or more pharmaceutical excipients;-   c) and    -   the coating of the present invention which provides protection        of one or more active substances and one or more pharmaceutical        excipients and the pharmaceutical dosage form from environmental        influences, preferably from oxidation and/or environmental        humidity and most preferably from oxidation or    -   any other coating known in the prior art when the coated        particles of the present invention are embedded in the coated        pharmaceutical dosage form.

The uncoated particles in the context of the present invention are theparticles which do not include the coating of the present invention orany other coating known in the prior art.

Further object of the present invention is the uncoated pharmaceuticaldosage form which comprises:

-   a) one or more coated particles of the present invention containing    one or more active substances of the present invention which are    sensitive to environmental influences, preferably to oxidation and    environmental humidity and most preferably to oxidation;-   b) one or more pharmaceutical excipients.

The active substance of the present invention embedded in the coated oruncoated pharmaceutical dosage form of the present invention is selectedfrom the group consisting of HMG-CoA reductase inhibitor, captopril,chlorpromazine, morphine, L-ascorbic acid, vitamin E, phenylbutazone,tetracyclines and omeprazole. Preferably an active substance of thepresent invention is an HMG-CoA reductase inhibitor selected from thegroup consisting of pravastatin, atorvastatin, rosuvastatin,itavastatin, simvastatin and lovastatin.

The pharmaceutical dosage form of the present invention and particles ofregular or irregular shapes of the present invention such asmicrocapsules, microspheres, granules, pellets and the like comprise oneor more pharmaceutical excipients which are selected from the groupconsisting of:

a) one or more fillers;

b) one or more binders;

c) one or more disintegrants;

d) one or more lubricants or glidants;

e) one or more buffering components;

f) one or more alkalizing components;

g) one or more surfactants;

h) and other components for solid pharmaceutical dosage form known inthe prior art and which are selected from the group consisting ofcolorants, flavors and adsorbing substances.

The filler of the pharmaceutical dosage form of the present inventionmay be selected from the group consisting of microcrystalline cellulose(MCC), modified forms of microcrystalline cellulose, lactose, sugars,different types of starch, modified forms of starch, mannitol, sorbitoland other polyoles, dextrin, dextran and maltodextrin, calciumcarbonate, calcium phosphate and/or hydrogen phosphate, sulfate and anycombinations thereof. Fillers are added in concentrations 1-99% to thetotal weight of the pharmaceutical dosage form.

The binder of the pharmaceutical dosage form of the present inventionmay be selected from the group consisting of lactose, different types ofstarch, modified forms of starch, dextrin, dextran and maltodextrin,microcrystalline cellulose (MCC), sugars, polyethylene glycols,hydroxypropyl cellulose, hydroxypropyl methylcellulose, ethylcellulose,hydroxyethyl cellulose, methylcellulose, carboxymethylcellulose, sodiumcarboxymethylcellulose, gelatin, acacia, tragacanth,polyvinylpyrrolidone, magnesium aluminium silicate and any combinationsthereof. Binders are added in concentrations 0.5-20% to the total massof the pharmaceutical dosage form.

The disintegrant of the pharmaceutical dosage form of the presentinvention may be selected from the group consisting of crosslinkedsodium carboxymethylcellulose, crosslinked polyvinylpyrrolidone,crosslinked carboxymethyl starch, different types of starch andmicrocrystalline cellulose, magnesium aluminium silicate, polacrilinpotassium and any combinations thereof. Disintegrants are added inconcentrations 2-20% to the total mass of the pharmaceutical dosageform.

The lubricant of the pharmaceutical dosage form of the present inventionmay be selected from the group consisting of magnesium, calcium and zincstearate, calcium behenate, sodium stearyl fumarate, talc, magnesiumtrisilicate, stearic acid, palmitic acid, carnauba wax, silicon dioxideand any combinations thereof. Lubricants or glidants are added inconcentrations 0.1-10% to the total mass of the pharmaceutical dosageform.

The buffering component of the pharmaceutical dosage form of the presentinvention is a salt of weak acid and strong base or a salt of strongacid and weak base or other similar substance which maintains the pHwithin the determined range. The buffering component may be selectedfrom the group consisting of:

a) alkali metal salts, alkali-earth-metal salts and ammonium salts ofcitric acid, ascorbic acid, malic acid, sorbic acid, succinic acid,benzoic acid, phosphoric acid, carbonic acid, sulfuric acid, nitricacid, boric acid and silicic acid;

b) amines in a combination with a strong or weak acid, such astrometamine (TRIS), EDTA;

c) ion exchangers; and

d) any combinations thereof.

Buffering components are added in concentrations 0-50% to the total massof the pharmaceutical dosage form.

The alkalizing component of the pharmaceutical dosage form of thepresent invention is selected from the group consisting of organic orinorganic compounds which contain the groups having alkaline action andmay be selected from the group consisting of:

a) oxides and hydroxides of alkaline and/or alkali-earth metals, oxidesof the 4, 5 and/or 6 group of the periodic system such as MgO, MgOH,NaOH, Ca(OH)₂;

b) amines such as trometamine (TRIS), ethanolamine, diethanolamine,triethanolamine, N-methyl-glucamine, glucosamine, ethylenediamine,diethylamine, triethylamine, isopropylamine, diisopropylamine;

c) alkali amino acids such as, e.g. arginine, histidine and lysine.

Alkalizing components are added in concentrations 0-50% to the totalmass of the pharmaceutical dosage form.

The surfactant of the pharmaceutical dosage form of the presentinvention may be selected from the group consisting of ionic surfactantssuch as sodium lauryl sulfate, nonionic surfactants such as differenttypes of poloxamers (copolymers of polyoxyethylene andpolyoxypropylene), natural or synthesized lecithins and esters ofsorbitan and fatty acids (such as Span® (Atlas Chemie)), esters ofpolyoxyethylenesorbitan and fatty acids (e.g. polyoxyethylene (20)sorbitan monooleate such as Polysorbate 80 and Tween® ((Atlas Chemie),respectively), polyoxyethylated hydrogenated castor oil (such asCremophor® (BASF)), polyoxyethylene stearates (such as Myrj® (AtlasChemie)) or cationic surfactants such as cetylpyridine chloride or anycombination of said surfactants. Surfactants are added in concentrations0-15% to the total mass of the pharmaceutical dosage form.

Other components for solid pharmaceutical dosage form are the componentswhich are known from the prior art and are conventional and used in theart of solid pharmaceutical dosage form. They are selected from thegroup consisting of colorants, flavoring agents and adsorbing materials.

The pharmaceutical dosage form of the present invention is preferablythe solid pharmaceutical dosage form.

The pharmaceutical dosage form of the present invention comprises activesubstances sensitive to environmental humidity have water content bellow5%, preferably below 4% and the most preferably below 3% by weight ofthe entire pharmaceutical dosage form. The pharmaceutical dosage form ofthe present invention prevents conversion of the active substanceHMG-CoA reductase inhibitor from a hydroxyl acid form to a lactone formunder the conditions of low humidity, that is, at 5% loss on drying (LODbellow 5%), preferably LOD bellow 4% and most preferably bellow 3%.

The object of the present invention is also the process for thepreparation of the coated particles of the present invention and thepharmaceutical dosage forms of the present invention.

Particles of regular or irregular shapes such as microcapsules,microspheres, granules, pellets and the like, and pharmaceutical dosageforms such as tablets, capsules and the like, of the present inventioncan be prepared with any in prior art known process, for example:

-   -   A mixture of one or more coated and/or one or more uncoated        active substances, a filler, a binder, a buffering agent, an        alkalizing agent, a disintegrant and if required a surfactant        and other conventional ingredients for a solid pharmaceutical        dosage form are homogenized in suitable mixers, the mixture is        compacted in suitable compaction machines or slugged in slugging        machines or conventional tablet presses, the compacts and or        slugs are triturated and/or sieved, fillers, buffering agents,        disintegrants, glidants, lubricants and other conventional        pharmaceutical excipients for tablets or capsules are added, and        the mixture is homogenized. The resulting mixture is compressed        into tablets or filled into capsules;    -   A mixture of one or more coated and/or one or more uncoated        therapeutic active substances, a filler, a binder, buffering        agent, alkalizing agent, a disintegrant and if required a        surfactant and other conventional ingredients for a solid        pharmaceutical dosage form is homogenized in suitable mixers,        glidants and lubricants are added and the mixture is        homogenized. The resulting mixture is compressed into tablets or        filled into capsules;    -   A solution of a buffering component and if required a binder, a        surfactant and a disintegrant is sprayed in the warm air flow        onto a filler, a mixture of one or more coated and/or uncoated        therapeutic active substances is added, and if required a        binder, a buffering component, alkalizing agent, a disintegrant,        a surfactant and other conventional components for solid        pharmaceutical dosage forms, the mixture is homogeneously mixed        in suitable mixers, glidants and lubricants are added and the        mixture is homogenized. The resulting mixture is compressed into        tablets or filled into capsules;    -   A mixture of one or more coated and/or one or more uncoated        therapeutic active substance, a filler, a binder, a buffering        agent, alkalizing agent, a disintegrant and if required a        surfactant and other conventional ingredients for a solid        pharmaceutical dosage forms is homogenized in suitable mixers,        granulated with a suitable solvent such as water, ethanol,        methanol, isopropyl alcohol, n-butyl alcohol, acetone,        diethylether, ethylacetate, isopropylacetate, methylacetate,        dichloromethane, chloroform, mixtures of said solvents such as        ethanol and acetone, methanol and acetone, dichloromethane and        methanol, and mixtures thereof. The resulting granulate is dried        in suitable dryers such as standard plate dryers, fluidized bed        dryers, vacuum and microwave dryers, at a temperature not        exceeding 60° C. To the dried granulate are added fillers,        disintegrants, buffering agents, alkalizing agent, glidants and        lubricants and if required other conventional ingredients for        solid pharmaceutical dosage forms. The resulting mixture is        homogenized and compressed into tablets or filled into capsules.

When required, the active substance, particles of regular or irregularshapes, such as microcapsules, microspheres, granules, pellets and thelike, and pharmaceutical dosage forms such as tablets, capsules and thelike, may be coated with the coating of the present invention and whichprovides protection of the active substance from environmental factors,preferably from oxidation. In the case of said coated particlesincorporated in pharmaceutical dosage forms such as tablets, capsules,and the like, said pharmaceutical dosage forms may be coated with anyother in the prior art known coating.

Particles or pharmaceutical dosage forms of the present invention can becoated by any process known in the prior art, for example:

A mixture of one or more film formers, a plasticizer and optionally oneor more excipients from following groups: viscosity-increasing agent,filler, glidant, colorant, surfactant, buffering component, alkalizingcomponent and other excipients, is prepared by dispersing and dissolvingin a solvent and then sprayed onto the active substance, particles ofregular or irregular shapes such as, e.g. microcapsules, microspheres,granules, pellets and the like, and pharmaceutical dosage forms such as,e.g. tablets, capsules in suitable coating equipment.

If necessary, coating process can also be provided in an inertatmosphere, such as nitrogen, argon or carbon dioxide atmosphere.

The object of the present invention is further use of the activesubstance in the context of said invention for the preparation of thecoated particles and/or pharmaceutical dosage forms for the treatmentand the method of treatment of different diseases by administering thecoated particles and/or pharmaceutical dosage forms wherein the diseasesare selected from the group consisting of dyslipidemia, hyperlipidemia,hypercholesterolemia, atherosclerosis, arteriosclerosis, cardiovasculardisease, coronary artery disease, coronary heart disease, vasculardisorder, inflammatory disease, allergic disease, neurodegenerativedisease, malignant disease, viral disease (WO 0158443), abnormal bonestates (WO 0137876), amyloid-(precursor protein processing disorderssuch as Alzheimer's disease of Down's Syndrome (WO0132161).

The invention will be explained with reference to the accompanyingexamples, which are illustrative and should not be construed as limitingscope of the invention.

EXAMPLES

All herein presented examples referring to atorvastatin includeamorphous atorvastatin Ca.

Example 1 Composition of One Coated Tablet

1.1. Tablet Core

TABLE 2 Composition of the core Ingredient Mass (mg) Atorvastatin (inthe form of atorvastatin Ca) 20.00 Microcrystalline cellulose 143.20Lactose monohydrate 34.80 Crosslinked carboxymethylcellulose 19.20Hydroxypropyl cellulose 2.00 Polysorbate 80 2.60 Magnesium oxide 26.00Colloidal silicon dioxide 1.20 Magnesium stearate 1.00Preparation of Tablet Core

Atorvastatin, half of microcrystalline cellulose, lactose monohydrate,half of crosslinked carboxymethylcellulose and 11% of the totalmagnesium oxide were homogeneously mixed and granulated with a solutionof hydroxypropyl cellulose and polysorbate in water. The granulate wasdried in a fluid bed dryer and the sieved granulate was homogeneouslymixed with the other half of microcrystalline cellulose and crosslinkedcarboxymethylcellulose, the rest of magnesium oxide, colloidal silicondioxide and magnesium stearate. The homogeneous granulate was compressedinto tablets, mass 250 mg, on a conventional tablet press.

1.2. Tablet Coating

TABLE 3 Composition of a coating Weight of coating in respect to coremass (%) and mass of ingredients in a coating (mg) Coating ingredients6% 8% Sodium carboxymenthylcellulose 14.00 mg 18.64 mg Glycerol  1.40 mg 1.86 mgPreparation of a Coating Dispersion and Coating of Tablet Cores

Sodium carboxymethylcellulose (Blanose CMC 7LF PH, Aqualon), (111.84 g)with viscosity 25 to 50 mPas and glycerol (11.16 g) while mixing weredissolved in water (2576.40 g). The resulting dispersion was sprayedonto the cores to obtain different coatings 6% and 8% by weight inrespect to core mass. During the coating process the tablet mass wascontrolled and thus the mass of coating was determined.

1.3. Analysis of Stability of the Active Substance in the PharmaceuticalDosage Form of Example 1 in Different Atmospheres

The effect of the protective coating was tested by the stress test at60° C. 14 days in nitrogen, air and oxygen atmosphere. The assay ofoxidative products of atorvastatin in the tablets was determined byliquid chromatography. As reference sample the tablets stored at 4° C.were analyzed. Coated tablets were compared with uncoated tablet cores.

TABLE 4 Increase of the assay of degradation products of atorvastatin inthe tablets stored 14 days at 60° C. in nitrogen, air and oxygenatmosphere versus the tablets stored at 4° C. Weight of Increase of theassay of Weight of coating glycerol in degradation products in %Pharmaceutical in respect to core respect to mass in differentatmospheres dosage form mass (%) of Na CMC (%) Nitrogen Air OxygenReference of Example 1 - 0 0 0.24 1.01 3.45 uncoated tablet Coatedtablet of 6 10 0.19 0.28 0.32 Example 1 Coated tablet of 8 10 0.38 0.320.19 Example 1

An increase of the degradation products of atorvastatin in the uncoatedtablet in comparison to the coated tablet of Example 1 is approximatelythree times greater for the samples in air atmosphere and more than tentimes greater for the samples in oxygen atmosphere. The coating ofExample 1 prevents ingress of oxygen to the tablet core and to theactive substance thus preventing occurrence of degradation products ofthe active substance.

Example 2 Composition of One Coated Tablet

2.1. Tablet Core

TABLE 5 Composition of the core Ingredient Mass (mg) Atorvastatin (inthe form of atorvastatin Ca) 10.00 Microcrystalline cellulose 153.20Lactose monohydrate 34.80 Crosslinked carboxymethylcellulose 19.20Hydroxypropyl cellulose 2.00 Polysorbate 80 2.60 Magnesium oxide 26.00Colloidal silicon dioxide 1.20 Magnesium stearate 1.00Preparation of Tablet Core

Atorvastatin, 53% of the total microcrystalline cellulose, lactosemonohydrate, half of crosslinked carboxymethylcellulose and 11% of thetotal magnesium oxide were homogeneously mixed and granulated with asolution of hydroxypropyl cellulose and polysorbate in water. Thegranulate was dried in a fluid bed dryer and the sieved granulate washomogeneously mixed with the rest of microcrystalline cellulose,crosslinked carboxymethylcellulose and magnesium oxide, colloidalsilicon dioxide and magnesium stearate. The homogeneous granulate wascompressed into tablets, mass 250 mg, on a conventional tablet press.

2.2. Tablet Coating

TABLE 6 Composition of a coating Weight of coating in respect to coremass (%) and mass of ingredients in a coating (mg) Coating ingredients6% 8% Sodium carboxymenthylcellulose 14.000 mg  18.640 mg  Glycerol1.400 mg 1.860 mg Titanium dioxide 1.586 mg 2.082 mg Pigment yellow0.014 mg 0.018 mgPreparation of a Coating Dispersion and Coating of Tablet Cores

Sodium carboxymethylcellulose (Blanose CMC 7LF PH, Aqualon), (111.84 g)with viscosity 25 to 50 mPas and glycerol (11.16 g) while mixing weredissolved in water (2576.40 g) and then while mixing a dispersion ofcoloring concentrate was added. A coloring concentrate was prepared bydispersing an aqueous dispersion of titanium dioxide (12.492 g) andpigment yellow (Sicopharm 10, BASF), (0.108 g). The resulting dispersionwas sprayed onto the cores to obtain two different coatings 6.6% and8.8% by weight in respect to core mass. During the coating process thetablet mass was controlled and thus the mass of coating was determined.

2.3. Analysis of Stability of the Active Substance in the PharmaceuticalDosage Form of Example 2 in Different Atmospheres

The effect of the protective coating was tested as described in Example1.

TABLE 7 Increase of the assay of degradation products of atorvastatin inthe tablets stored 14 days at 60° C. in nitrogen, air and oxygenatmosphere versus the tablets stored at 4° C. Weight of Increase of theassay of Weight of glycerol in degradation products in % inPharmaceutical coating in respect respect to mass different atmospheresdosage form to core mass (%) of Na CMC (%) Nitrogen Air Oxygen Referenceof Example 2 - 0 0 0.03 1.07 4.04 uncoated tablet Coated tablet of 6.610 0.08 0.08 0.06 Example 2 Coated tablet of 8.8 10 0.05 0.00 0.04Example 2

An increase of the degradation products of atorvastatin in the uncoatedtablet in comparison to the coated tablet of Example 2 is approximatelymore than ten times greater for the samples in air atmosphere and morethan sixty times greater for the samples in oxygen atmosphere. Thecoating of Example 2 effectively prevents ingress of oxygen to thetablet core and to the active substance thus preventing occurrence ofdegradation products of the active substance.

Example 3 Composition of One Coated Tablet

3.1. Tablet Core

TABLE 8 Composition of the core Ingredient Mass (mg) Atorvastatin (inthe form of atorvastatin Ca) 10.00 Microcrystalline cellulose 153.20Lactose monohydrate 34.80 Crosslinked carboxymethylcellulose 19.20Hydroxypropyl cellulose 2.00 Polysorbate 80 2.60 Magnesium ixide 26.00Colloidal silicon dioxide 1.20 Magnesium stearate 1.00Preparation of Tablet Core

Atorvastatin, 53% of the total microcrystalline cellulose, lactosemonohydrate, half of crosslinked carboxymethylcellulose and 11% of thetotal magnesium oxide were homogeneously mixed and granulated with asolution of hydroxypropyl cellulose and polysorbate in water. Thegranulate was dried in a fluid bed dryer and the sieved granulate washomogeneously mixed with the rest of microcrystalline cellulose,crosslinked carboxymethylcellulose and magnesium oxide, colloidalsilicon dioxide and magnesium stearate. The homogeneous granulate wascompressed into tablets, mass 250 mg, on a conventional tablet press.

3.2. Tablet Coating

TABLE 4 Composition of a coating Weight of coating in respect to coremass (%) and mass of ingredients in a coating (mg) Coating ingredients6.6% 8.7% Sodium carboxymenthylcellulose 14.00 mg 18.64 mg Glycerol 2.80 mg  3.73 mgPreparation of a Coating Dispersion and Coating of Tablet Cores

Sodium carboxymethylcellulose (Blanose CMC 7LF PH, Aqualon), (111.84 g)with viscosity 25 to 50 mPas and glycerol (22.38 g) while mixing weredissolved in water (2576.40 g). The resulting dispersion was sprayedonto the cores to obtain two different coatings 6% and 8% by weight inrespect to core mass. During the coating process the tablet mass wascontrolled and thus the mass of coating was determined.

3.3. Analysis of Stability of the Active Substance in the PharmaceuticalDosage Form of Example 3 in Different Atmospheres

The effect of the protective coating was tested as described in Example1.

TABLE 10 Increase of the assay of degradation products of atorvastatinin the tablets stored 14 days at 60° C. in nitrogen, air and oxygenatmosphere versus the tablets stored at 4° C. Weight of Increase of theassay of Weight of glycerol in degradation products in % inPharmaceutical coating in respect respect to mass different atmospheresdosage form to core mass (%) of Na CMC (%) Nitrogen Air Oxygen Referenceof Example 3 - 0 0 0.03 1.07 4.04 uncoated tablet Coated tablet of 6.620 0.05 0.06 0.03 Example 3 Coated tablet of 8.7 20 0.04 0.00 0.00Example 3

Similar to Example 2, an increase of the degradation products ofatorvastatin in the uncoated tablet in comparison to the coated tabletof Example 3 is approximately more than ten times greater for thesamples in air atmosphere and more than hundred times greater for thesamples in oxygen atmosphere. The coating of Example 3 effectivelyprevents ingress of oxygen to the tablet core and to the activesubstance thus preventing occurrence of degradation products of theactive substance.

Example 4 Composition of One Coated Tablet

4.1. Tablet Core

TABLE 11 Composition of the core Ingredient Mass (mg) Atorvastatin (inthe form of atorvastatin Ca) 10.00 Microcrystalline cellulose 153.20Lactose monohydrate 34.80 Crosslinked carboxymethylcellulose 19.20Hydroxypropyl cellulose 2.00 Polysorbate 80 2.60 Magnesium oxide 26.00Colloidal silicon dioxide 1.20 Magnesium stearate 1.00Preparation of Tablet Core

Atorvastatin, 53% of the total microcrystalline cellulose, lactosemonohydrate, half of crosslinked carboxymethylcellulose and 11% of thetotal magnesium oxide were homogeneously mixed and granulated with asolution of hydroxypropyl cellulose and polysorbate in water. Thegranulate was dried in a fluid bed dryer and the sieved granulate washomogeneously mixed with the rest of microcrystalline cellulose,crosslinked carboxymethylcellulose and magnesium oxide, colloidalsilicon dioxide and magnesium stearate. The homogeneous granulate wascompressed into tablets, mass 250 mg, on a conventional tablet press.

4.2. Tablet Coating

TABLE 12 Composition of a coating Weight of coating in respect to coremass (%) and mass of ingredients in a coating (mg) Coating ingredients7.1% 9.5% Sodium carboxymenthylcellulose 14.00 mg 18.64 mg Glycerol 4.20 mg  5.59 mgPreparation of a Coating Dispersion and Coating of Tablet Cores

Sodium carboxymethylcellulose (Blanose CMC 7LF PH, Aqualon), (111.84 g)with viscosity 25 to 50 mPas and glycerol (33.54 g) while mixing weredissolved in water (2576.40 g). The resulting dispersion was sprayedonto the cores to obtain different coatings 7.1% and 9.5% by weight inrespect to core mass. During the coating process the tablet mass wascontrolled and thus the mass of coating was determined.

4.3. Analysis of Stability of the Active Substance in the PharmaceuticalDosage Form of Example 4 in Different Atmospheres

The effect of the protective coating was tested as described in Example1.

TABLE 13 Increase of the assay of degradation products of atorvastatinin the tablets stored 14 days at 60° C. in nitrogen, air and oxygenatmosphere versus the tablets stored at 4° C. Weight of Increase of theassay of Weight of glycerol in degradation products in % inPharmaceutical coating in respect respect to mass different atmospheresdosage form to core mass (%) of Na CMC (%) Nitrogen Air Oxygen Referenceof Example 4 - 0 0 0.03 1.07 4.04 uncoated tablet Coated tablet of 7.130 0.05 0.00 0.07 Example 4 Coated tablet of 9.5 30 0.01 0.02 0.03Example 4

The increase of degradation products in air and in oxygen atmosphere areextremely low. The coating of Example 4 effectively prevents ingress ofoxygen to the tablet core and to the active substance thus preventingoccurrence of degradation products of the active substance similar tothe Example 2 and 3.

Example 5 Composition of One Coated Tablet

5.1. Tablet Core

TABLE 14 Composition of the core Ingredient Mass (mg) Atorvastatin (inthe form of atorvastatin Ca) 40.00 Sodium lauryl sulfate 30.0 ProSolv HD90 160.00 Pregelitinized corn starch 3.75 Crosslinkedcarboxymethylcellulose 12.50 Magnesium stearate 1.25 Talc 2.50Preparation of Tablet Core

Atorvastatin Ca, ProSolv HD 90, sodium lauryl sulfate, pregelatinizedcorn starch and crosslinked carboxymethylcellulose were homogeneouslymixed. Magnesium stearate and talc were added, homogeneously mixed andcompressed into tablets, mass 250 mg, in a room with controlled lowrelative air humidity.

5.2. Tablet Coating

TABLE 15 Composition of a coating Weight of coating in respect to coremass (%) and mass of ingredients in a coating (mg) Coating ingredients6% 8% Sodium carboxymenthylcellulose 12.275 mg  16.363 mg  Glycerol1.225 mg 1.637 mg Titanium dioxide 1.406 mg 1.875 mg Pigment yellow0.094 mg 0.125 mgPreparation of a Coating Dispersion and Coating of Tablet Cores

Sodium carboxymethylcellulose (Blanose CMC 7LF PH, Aqualon), (98.178 g)with viscosity 25 to 50 mPas and glycerol (9.822 g) while mixing weredissolved in water (2230 g) and then while mixing a dispersion ofcoloring concentrate was added. A coloring concentrate was prepared bydispersing an aqueous dispersion of titanium dioxide (11.250 g) andpigment yellow (Sicopharm 10, BASF), (0.750 g). The resulting dispersionwas sprayed onto the cores to obtain two different coatings 6% and 8% byweight in respect to core mass. During the coating process the tabletmass was controlled and thus the mass of coating was determined.

Example 6 Composition of One Coated Tablet

6.1. Tablet Core

TABLE 16 Composition of the core Ingredient Mass (mg) Atorvastatin (inthe form of atorvastatin Ca) 40.00 Sodium lauryl sulfate 30.0 ProSolvSMCC 90 149.00 Na₃PO₄•12H₂O 11.00 Pregelitinized corn starch 3.75Crosslinked carboxymethylcellulose 12.50 Magnesium stearate 1.25 Talc2.50Preparation of Tablet Core

A solution of Na₃PO₄.12H₂O was dispersed in the stream of warm air onProSolv SMCC 90. The resulting granulate was dried and sieved.Atorvastatin, sodium lauryl sulfate, pregelatinized corn starch andcrosslinked carboxymethylcellulose were added and then homogeneouslymixed. Magnesium stearate and talc were added, homogeneously mixed andcompressed into tablets, mass 250 mg, in a room with controlled lowrelative air humidity.

6.2. Tablet Coating

TABLE 17 Composition of a coating Weight of coating in respect to coremass (%) and mass of ingredients in a coating (mg) Coating ingredients6% 8% Sodium carboxymenthylcellulose 12.275 mg  16.363 mg  Glycerol1.225 mg 1.637 mg Titanium dioxide 1.406 mg 1.875 mg Pigment yellow0.094 mg 0.125 mgPreparation of a Coating Dispersion and Coating of Tablet Core

Sodium carboxymethylcellulose (Blanose CMC 7LF PH, Aqualon), (98.178 g)with viscosity 25 to 50 mPas and glycerol (9.822 g) while mixing weredissolved in water (2230 g) and then while mixing a dispersion ofcoloring concentrate was added. A coloring concentrate was prepared bydispersing an aqueous dispersion of titanium dioxide (11.250 g) andpigment yellow (Sicopharm 10, BASF), (0.750 g). The resulting dispersionwas sprayed onto the cores to obtain two different coatings 6% and 8% byweight in respect to core mass. During the coating process the tabletmass was controlled and thus the mass of coating was determined.

Example 7 Composition of One Coated Tablet

7.1. Tablet Core

TABLE 16 Composition of the core Ingredient Mass (mg) Atorvastatin (inthe form of atorvastatin Ca) 40.00 Sodium lauryl sulfate 30.00 ProSolvSMCC 90 110.00 Na citrate dihydrate 50.00 Pregelitinized corn starch3.75 Crosslinked carboxymethylcellulose 12.50 Magnesium stearate 1.25Talc 2.50Preparation of Tablet Core

A solution of Na citrate dihydrate was dispersed in the stream of warmair on ProSolv SMCC 90. The resulting granulate was dried and sieved.Atorvastatin, sodium lauryl sulfate, pregelatinized corn starch andcrosslinked carboxymethylcellulose were added and then homogeneouslymixed. Magnesium stearate and talc were added, homogeneously mixed andcompressed into tablets, mass 250 mg, in a room with controlled lowrelative air humidity.

7.2. Tablet Coating

TABLE 19 Composition of a coating Weight of coating in respect to coremass (%) and mass of ingredients in a coating (mg) Coating ingredients6% 8% Sodium carboxymenthylcellulose 12.275 mg  16.363 mg  Glycerol1.225 mg 1.637 mg Titanium dioxide 1.406 mg 1.875 mg Pigment yellow0.094 mg 0.125 mgPreparation of a Coating Dispersion and Coating of Tablet Core

Sodium carboxymethylcellulose (Blanose CMC 7LF PH, Aqualon), (98.178 g)with viscosity 25 to 50 mPas and glycerol (9.822 g) while mixing weredissolved in water (2230 g) and then while mixing a dispersion ofcoloring concentrate was added. A coloring concentrate was prepared bydispersing an aqueous dispersion of titanium dioxide (11.250 g) andpigment yellow (Sicopharm 10, BASF), (0.750 g). The resulting dispersionwas sprayed onto the cores to obtain two different coatings 6% and 8% byweight in respect to core mass. During the coating process the tabletmass was controlled and thus the mass of coating was determined.

Example 8 Composition of One Coated Tablet

8.1. Tablet Core

TABLE 20 Composition of the core Ingredient Mass (mg) Atorvastatin (inthe form of atorvastatin Ca) 40.00 Sodium lauryl sulfate 5.00 ProSolvSMCC 90 139.00 Pregelitinized corn starch 3.00 Crosslinkedcarboxymethylcellulose 10.00 Magnesium stearate 1.00 Talc 2.00Preparation of Tablet Core

A solution of sodium lauryl sulfate was dispersed in the stream of warmair on atorvastatin Ca. The resulting granulate was dried and sieved.ProSolv SMCC 90, pregelitinized corn starch and crosslinkedcarboxymethylcellulose were homogeneously mixed. Magnesium stearate andtalc were added, homogeneously mixed and compressed into tablets, mass200 mg.

8.2. Tablet Coating

TABLE 21 Composition of a coating Weight of a coating in respect to coremass (%) and ingredient mass in a core Coating ingredients (mg) 8%Sodium carboxymethylcellulose 14.90 mg Glycerol  1.50 mgPreparation of a Coating Dispersion and Coating of Tablet Cores

Sodium carboxymethylcellulose (Blanose CMC 7LF PH, Aqualon), (109.00 g)with viscosity 25 to 50 mPas and glycerol (11.00 g) while mixing weredissolved in water (2513.60 g). The resulting dispersion was sprayedonto the cores to obtain an 8% coating by weight in respect to coremass. During the coating process the tablet mass was controlled and thusthe mass of coating was determined.

8.3. Determination of the pH Value of Tablets

The pH value of the tablet of Example 8, determined potentiometrically,was 6.7. By the same procedure, the pH value of the mixture atorvastatinCa and ProSolv SMCC 90 (mixture in a ratio equivalent to their ratio byweight in a tablet) was determined, and it was 7.93.

The pH values of the tablet and the mixture of the active substance andthe filler ProSolvSMOC 90 were determined in 20 ml aqueous dispersion of1 tablet with the assay of 40 mg atorvastatin Ca, that is, in thedispersion of the mixture of the active substance and the filler ProSolvSMCC 90 in the amount present in said tablet. The pH value wasdetermined on analytical equipment 720 KFS Titrino Methrom usingcombined micro pH electrode Methrom 6.0204.100 pH 14/0 70° C.

8.4 Analysis of Stability of the Active Substance in the PharmaceuticalDosage Form of Example 8 in Different Atmospheres

The influence of water/humidity and pharmaceutical excipients onoccurrence of degradation products (lactone and oxidative degradationproducts) was assessed by testing coated tablets in the packages (HDPEplastic bottles) with different desiccants (without desiccant, silicagel, molecular sieves). Coated tablets were stored for 1 month under theconditions 40/75 (40° C.±2° C., 75% RH±5%). The assay of degradationproducts of atorvastatin (lactone and oxidative degradation products)was determined by liquid chromatography. As reference sample the tabletsstored in a refrigerator (2-8° C.) were analyzed. The moisture contentin the tablets was measured gravimetrically by determining loss ondrying (LOD).

TABLE 22 Increase in the assay of degradation products of atorvastatin(lactone) in the coated tablets of said invention, stored 1 month underthe conditions 40/75 (40° C. ± 2° C., 75% RH ± 5%) Increase of lactoneLOD* assay in % to Desiccant (%) Storage conditions reference sampleReference sample 5.08 Refrigerator, 1 month (reference) withoutdesiccant 5.17 40/75, 1 month 0.21 2 g silica gel 3.49 40/75, 1 month0.05 4 g silica gel 2.73 40/75, 1 month 0.04 2 g molecular sieves 1.9940/75, 1 month 0.03 4 g molecular sieves 1.55 40/75, 1 month 0.03 2 gsilica gel + 2 g 1.73 40/75, 1 month 0.03 molecular sieves LOD*-loss ondrying

After one month of testing under the condition of accelerated stabilityit was observed that due to smaller percent of moisture in the tabletswith added desiccant, lactone in said tablets was formed in aconsiderably smaller percent (level 0.05%) compared to the tablets withno added desiccant (level 0.22%). Under the determined level ofhumidity, differences in the percentage of formed lactone in thetablets, i.e. below 3.50% of moisture estimated as loss on drying werenot significant.

TABLE 23 Increase in the assay of degradation products of atorvastatin(oxidative degradation products in the coated tablets of said invention,stored 1 month under the conditions 40/75 (40° C. ± 2° C., 75% RH ± 5%)Increase in assay of oxidative degradation products in % to referencesample Coated tablets LOD* Storage Uncoated according to Desiccant (%)conditions tablets Example 8 Reference sample 5.08 Refrigerator, 1 month(reference) without desiccant 5.17 40/75, 1 month 0.20 0.14 2 g silicagel 3.49 40/75, 1 month 0.42 0.12 4 g silica gel 2.73 40/75, 1 month0.34 0.12 2 g molecular sieves 1.99 40/75, 1 month 0.43 0.15 4 gmolecular sieves 1.55 40/75, 1 month 0.38 0.13 2 g silica gel + 2 g 1.7340/75, 1 month 0.36 0.11 molecular sieves LOD*-loss on drying

After one month of testing under the condition of accelerated stabilitythe increase of degradation products of atorvastatin (oxidativedegradation products) in the coated tablet of said invention wassignificantly smaller than in the uncoated tablet.

Example 9 Composition of One Coated Tablet

9.1. Tablet Core

TABLE 24 Composition of the core Ingredient Mass (mg) Atorvastatin (inthe form of atorvastatin Ca) 20.00 Microcrystalline cellulose 143.20Lactose monohydrate 34.80 Crosslinked carboxymethylcellulose 19.20Hydroxypropyl cellulose 2.00 Polysorbate 80 2.60 Magnesium oxide 26.00Colloidal silicon dioxide 1.20 Magnesium stearate 1.00Preparation of Tablet Core

Atorvastatin, a part of microcrystalline cellulose, lactose monohydrate,a part of crosslinked carboxymethylcellulose and a part of magnesiumoxide were homogeneously mixed and granulated with a solution ofhydroxypropyl cellulose and polysorbate in water. The granulate wasdried in a fluid bed dryer and the sieved granulate was homogeneouslymixed with a part of microcrystalline cellulose, a part of crosslinkedcarboxymethylcellulose, a part of magnesium oxide, colloidal silicondioxide and magnesium stearate. The homogeneous granulate was compressedinto tablets, mass 250 mg, on a conventional tablet press.

9.2. Tablet Coating

TABLE 25 Composition of a coating Weight of coating in respect to coremass (%) and mass of ingredients in a coat (mg) Coating ingredients 6%8% Sodium carboxymenthylcellulose 9,800 mg 14,350 mg Polivinyl alcohol5,600 mg  6,150 mgPreparation of a Coating Dispersion and Coating of Tablet Cores

Polyvinyl alcohol (Mowiol 28-99, Fluca) (36,900 g) was stirred into thewater at room temperature. The mixture was then heated to 90° C., mixedfor 5 minutes and then cooled to room temperature. Then the Sodiumcarboxymethylcellulose (Blanose CMC 7LF PH, Aqualon), (86,100 g) withviscosity 25 to 50 mPas while mixing was added and stirred for 60minutes. The resulting dispersion was sprayed onto the cores to obtaindifferent coatings 6% and 8% by weight in respect to core mass. Duringthe coating process the tablet mass was controlled and thus the mass ofcoating was determined.

Example 10 Composition of One Coated Tablet

10.1. Tablet Core

TABLE 26 Composition of the core Ingredient Mass (mg) Atorvastatin (inthe form of atorvastatin Ca) 40.00 Sodium lauryl sulfate 10.00 Pigmentyellow 0.72 Tris 5.00 ProSolv HD 90 389.48 Sodium Starch Glycolate 28.80Magnesium stearate 1.20 Talc 4.80Preparation of Tablet Core

First, a triturate of pigment yellow and a part of ProSolv was preparedand then homogenized with the rest of ProSolv. Atorvastatin, Tris,sodium lauryl sulfate, sodium starch glycolate were added andhomogeneously mixed, Magnesium stearate and talc were added,homogeneously mixed and compressed into tablets, mass 480 mg.

10.2. Tablet Coating

TABLE 27 Composition of a coating Coating ingredients Mass ofingredients in the coating (mg) Sodium carboxymethylcellulose 31.700 mgGlycerol  6.300 mgPreparation of a Coating Dispersion and Coating of Tablet Core

Sodium carboxymethylcellulose (Blanose CMC 7LF PH, Aqualon), (85.59 g)with viscosity 25 to 50 mPas and glycerol (Cognis), (17.01 g) whilemixing were dissolved in water (1466.10 g). The resulting dispersion wassprayed onto the cores to an 8% coating by weight in respect to coremass During the coating process the tablet mass was controlled and thusthe mass of coating was determined.

10.3. Disintegration of Coated Tablets

Disintegration of coated tablets was determined with the disintegrationtest apparatus (Charles Isci, without discs) in 0.01 M HCl at 37° C.Disintegration was tested on 12 tablets. The average disintegration timeof 11 tablets is 419.7 s. One of the tablets was not disintegrated evenafter 15 minutes. The time, when water perfuses through coating isdecisive for coated tablet disintegration.

10.4. Analysis of Stability of the Active Substance in thePharmaceutical Dosage Form of Example 10 in Different Atmospheres

The effect of the protective coating was tested as described in Example1.

TABLE 28 Increase of the assay of degradation products of atorvastatinin the tablets stored 14 days at 60° C. in nitrogen, air and oxygenatmosphere versus the tablets stored at 4° C. Weight of Increase of theassay of Weight of coating glycerol in degradation products in % inPharmaceutical in respect to core respect to mass different atmospheresformulation mass (%) of Na CMC (%) Nitrogen Air Oxygen Referenceexample - 0 0 0.02 1.48 4.72 uncoated tablet Coated tablet of 8 20 0.220.39 0.47 Example 10

The increase of the degradation products of atorvastatin in the uncoatedtablet in comparison to the coated tablet of Example 10 is approximatelymore than three times greater for the samples in air atmosphere andabout ten times greater for the samples in oxygen atmosphere. Thecoating of Example 10 prevents ingress of oxygen to the tablet core andto the active substance thus preventing occurrence of degradationproducts of the active substance.

Example 11 Composition of One Coated Tablet

11.1. Tablet Core

Tablet cores from Example 1 were used.

11.2. Tablet Coating

TABLE 29 Composition of a coating Coating ingredients Mass ofingredients in the coating (mg) Sodium carboxymethylcellulose 31.700 mg Glycerol 6.300 mg Tris 3.000 mgPreparation of a Coating Dispersion and Coating of Tablet Core

Sodium carboxymethylcellulose (Blanose CMC 7LF PH, Aqualon), (85.59 g)with viscosity 25 to 50 mPas, glycerol (Cognis), (17.01 g) and Tris(PharmaGrade, AppliChem), (8.10 g) while mixing were dissolved in water(1466.10 g). The resulting dispersion was sprayed onto the cores to an8% coating by weight in respect to core mass. During the coating processthe tablet mass was controlled and thus the mass of coating wasdetermined.

11.3. Disintegration of Coated Tablets

Disintegration of coated tablets was determined with the disintegrationtest apparatus (Charles Isci, without discs) in 0.01 M HCl at 37° C.Disintegration was tested on 12 tablets. The average disintegration timeis 284.7 s. Therefore, disintegration time of coated tablets issignificantly faster with the addition of alkalizing substance (Tris) incoating.

11.4. Analysis of Stability of the Active Substance in thePharmaceutical Dosage Form of Example 11 in Different Atmospheres

The effect of the protective coating was tested as described in Example1.

TABLE 30 Increase of the assay of degradation products of atorvastatinin the tablets stored 14 days at 60° C. in nitrogen, air and oxygenatmosphere versus the tablets stored at 4° C. Weight of Increase of theassay of Weight of coating glycerol in degradation products in % inPharmaceutical in respect to core respect to mass different atmospheresformulation mass (%) of Na CMC (%) Nitrogen Air Oxygen Referenceexample - 0 0 0.02 1.48 4.72 uncoated tablet Coated tablet of 8 20 0.220.21 0.24 Example 11

The increase of the degradation products of atorvastatin in the uncoatedtablet in comparison to the coated tablet of Example 11 is approximatelyseven times greater for the samples in air atmosphere and about twentytimes greater for the samples in oxygen atmosphere. The coating ofExample 11 prevents ingress of oxygen to the tablet core and to theactive substance thus preventing occurrence of degradation products ofthe active substance.

Example 12 Composition of One Coated Tablet

12.1. Tablet Core

Tablet cores from Example 1 were used.

12.2. Tablet Coating

TABLE 31 Composition of a coating Coating ingredients Mass ofingredients in the coating (mg) Sodium carboxymethylcellulose 31.700 mg Glycerol 6.300 mg Tris 3.000 mg Sodium lauryl sulfate 1.500 mgPreparation of a Coating Dispersion and Coating of Tablet Core

Sodium carboxymethylcellulose (Blanose CMC 7LF PH, Aqualon), (85.59 g)with viscosity 25 to 50 mPas, glycerol (Cognis), (17.01 g), Tris(PharmaGrade, AppliChem), (8.10 g) and sodium lauryl sulfate (TexaponK12, Cognis), (4.05 g) while mixing were dissolved in water (1466.10 g).The resulting dispersion was sprayed onto the cores to an 8% coating byweight in respect to core mass. During the coating process the tabletmass was controlled and thus the mass of coating was determined.

12.3. Disintegration of Coated Tablets

Disintegration of coated tablets was determined with the disintegrationtest apparatus (Charles Isci, without discs) in 0.01 M HCl at 37° C.Disintegration was tested on 12 tablets. The average disintegration timeis 287.7 s. Therefore, disintegration time of coated tablets issignificantly faster with the addition of alkalizing substance (Tris)and surfactant (sodium lauryl sulfate) in coating.

12.4. Analysis of Stability of the Active Substance in thePharmaceutical Dosage Form of Example 12 in Different Atmospheres

The effect of the protective coating was tested as described in Example1.

TABLE 32 Increase of the assay of degradation products of atorvastatinin the tablets stored 14 days at 60° C. in nitrogen, air and oxygenatmosphere versus the tablets stored at 4° C. Weight of Increase of theassay of Weight of coating glycerol in degradation products in % inPharmaceutical in respect to core respect to mass different atmospheresformulation mass (%) of Na CMC (%) Nitrogen Air Oxygen Reference example0 0 0.02 1.48 4.72 12 uncoated tablet Coated tablet of 8 20 0.23 0.230.28 Example 12

The increase of the degradation products of atorvastatin in the uncoatedtablet in comparison to the coated tablet of Example 12 is approximatelysix times greater for the samples in air atmosphere and about seventeentimes greater for the samples in oxygen atmosphere. The coating ofExample 12 prevents ingress of oxygen to the tablet core and to theactive substance thus preventing occurrence of degradation products ofthe active substance.

Example 13 Composition of One Coated Tablet

13.1. Tablet Core

TABLE 33 Composition of the core Ingredient Mass (mg) Atorvastatin (inthe form of atorvastatin Ca) 40.00 Sodium lauryl sulfate 7.00 Pigmentyellow 0.72 Tris 5.00 ProSolv HD 90 385.28 Sodium Starch Glycolate 28.80Pregelatinized corn starch 7.20 Magnesium stearate 1.20 Talc 4.80Preparation of Tablet Core

First, a triturate of pigment yellow and a part of ProSolv was preparedand then homogenized with the rest of ProSolv. Atorvastatin, Tris,sodium lauryl sulfate, pregelatinized corn starch, sodium starchglycolate were added and homogeneously mixed. Magnesium stearate andtalc were added, homogeneously mixed and compressed into tablets, mass480 mg.

13.2. Tablet Coating

TABLE 34 Composition of a coating Coating ingredients Mass ofingredients in the coating (mg) Sodium carboxymethylcellulose 35.700 mg Glycerol 7.100 mg Tris 3.000 mg Sodium lauryl sulfate 1.000 mgPreparation of a Coating Dispersion and Coating of Tablet Core

Sodium carboxymethylcellulose (Blanose CMC 7LF PH, Aqualon), (187.425 g)with viscosity 25 to 50 mPas, glycerol (Cognis), (37.275 g), Tris(PharmaGrade, AppliChem), (15.750 g) and sodium lauryl sulfate (TexaponK12, Cognis), (5.250 g) while mixing were dissolved in water (3223.500g). The resulting dispersion was sprayed onto the cores to an 9% coatingby weight in respect to core mass. During the coating process the tabletmass was controlled and thus the mass of coating was determined.

13.3. Disintegration of Coated Tablets

Disintegration of coated tablets was determined with the disintegrationtest apparatus (Charles Isci, without discs) in 0.01 M HCl at 37° C.Disintegration was tested on 24 tablets. The average disintegration timeis 387.4 s.

13.4. Analysis of Stability of the Active Substance in thePharmaceutical Dosage Form of Example 13 in Different Atmospheres

The effect of the protective coating was tested as described in Example1.

TABLE 35 Increase of the assay of degradation products of atorvastatinin the tablets stored 14 days at 60° C. in nitrogen, air and oxygenatmosphere versus the tablets stored at 4° C. Weight of Increase of theassay of Weight of coating glycerol in degradation products in % inPharmaceutical in respect to core respect to mass different atmospheresformulation mass (%) of Na CMC (%) Nitrogen Air Oxygen Referenceexample - 0 0 0.00 1.28 5.27 uncoated tablet Coated tablet of 9 20 0.260.23 0.27 Example 13

The increase of the degradation products of atorvastatin in the uncoatedtablet in comparison to the coated tablet of Example 13 is approximatelyfive times greater for the samples in air atmosphere and about nineteentimes greater for the samples in oxygen atmosphere. The coating ofExample 13 prevents ingress of oxygen to the tablet core and to theactive substance thus preventing occurrence of degradation products ofthe active substance.

Example 14 Tablet with Coated Active Substance

TABLE 36 Composition of a tablet with coated active substance IngredientMass (mg) Atorvastatin (in the form of atorvastatin Ca) 40.00 Sodiumcarboxymethylcellulose 3.20 Glycerol 0.32 Sodium lauryl sulfate 30.00Cellactose 80 133.48 Granulated mannitol 30.00 Crosslinkedcarboxymethylcellulose 10.00 Magnesium stearate 1.00 Talc 2.00Preparation of Tablet with Coated Active Substance

A colloidal solution of sodium carboxymethylcellulose and glycerol wasdispersed in the stream of warm air on atorvastatin Ca. The resultingcoated active substance was dried and sieved. Cellastose 80, sodiumlauryl sulfate, granulated mannitol and crosslinkedcarboxymethylcellulose were added and then homogeneously mixed.Magnesium stearate and talc were added, homogeneously mixed andcompressed into tablets, mass 250 mg.

The invention claimed is:
 1. A composition comprising at least oneparticle enclosed in a coating, wherein said particle comprises anactive ingredient which is a HMG-CoA reductase inhibitor, said activeingredient being susceptible to degradation upon exposure to oxidationor humidity or both, and a coating, wherein said coating comprises anadmixture of (a) a film-forming substance selected from the groupconsisting of polyvinyl alcohol, sodium carboxymethylcellulose,hydroxyethylcellulose and combinations thereof and (b) at least onepharmaceutical excipient selected from the group consisting of abuffering agent, an alkalizing agent and a surface active agent whereinthe film-forming substance is present in concentrations of 60-95% of theamount of the solids in the coating, said coating having a thicknesswithin the range of 5 μm to 200 μm and said coating confers stability tothe active ingredient against oxidation or humidity or both, and saidcoating enabling the release of the active substance in all parts of thegastrointestinal tract, regardless of the environmental pH value.
 2. Thecomposition according to claim 1 wherein the HMG-CoA reductase inhibitoris at least one selected from the group consisting of atorvastatin,fluvastatin, lovastatin, mevastatin, pravastatin, rosuvastatin andsimvastatin.
 3. The composition according to claim 1 wherein the coatingcomprises a film-forming substance which is polyvinyl alcohol.
 4. Thecomposition according to claim 1 wherein the coating comprises afilm-forming substance which is sodium carboxymethylcellulose.
 5. Thecomposition according to claim 1 wherein the coating further comprises afilm-forming substance which is hydroxyethylcellulose.
 6. Thecomposition according to claim 1 wherein the coating further comprises apharmaceutical excipient selected from the group consisting of aplasticizer, viscosity-increasing agent of a coating dispersion, filler,lubricant and colorant.
 7. The composition according to claim 1 whereinthe composition has a water content less than 5 weight percent, based onthe total weight of the composition.
 8. A composition comprising atleast one particle enclosed in a coating, wherein said particlecomprises an active ingredient which is a HMG-CoA reductase inhibitor,said active ingredient being susceptible to degradation upon exposure tooxidation or humidity or both, and a coating, wherein said coatingcomprises an admixture of (a) a film-forming substance selected from thegroup consisting of carboxymethylcellulose, hydroxyethylcellulose andcombinations thereof and (b) at least one pharmaceutical excipientselected from the group consisting of a buffering agent, an alkalizingagent and a surface active agent wherein the film-forming substance ispresent in concentrations of 60-95% of the amount of the solids in thecoating, said coating having a thickness within the range of 5 μm to 200μm and said coating confers stability to the active ingredient againstoxidation or humidity or both, and said coating enabling the release ofthe active substance in all parts of the gastrointestinal tract,regardless of the environmental pH value.
 9. The composition accordingto claim 8 wherein the HMG-CoA reductase inhibitor is at least oneselected from the group consisting of atorvastatin, fluvastatin,lovastatin, mevastatin, pravastatin, rosuvastatin and simvastatin. 10.The composition according to claim 8 wherein the coating comprises afilm-forming substance which is sodium carboxymethylcellulose.
 11. Thecomposition according to claim 8 wherein the coating comprises afilm-forming substance which is hydroxyethylcellulose.
 12. A compositioncomprising at least one particle enclosed in a coating, wherein saidparticle comprises an active ingredient which is a HMG-CoA reductaseinhibitor, said active ingredient being susceptible to degradation uponexposure to oxidation or humidity or both, and a coating, wherein saidcoating comprises an admixture of sodium carboxymethylcellulose andtromethamine, wherein the film-forming substance is present inconcentrations of 60-95% of the amount of the solids in the coating,said coating having a thickness within the range of 5 μm to 200 μm andsaid coating confers stability to the active ingredient againstoxidation or humidity or both, and said coating enabling the release ofthe active substance in all parts of the gastrointestinal tract,regardless of the environmental pH value.
 13. A composition comprisingone or more particles enclosed in a coating, wherein said particlescomprise an active ingredient which is atorvastatin calcium, said activeingredient being susceptible to degradation upon exposure to oxidationor humidity or both, and a coating, wherein said coating comprises anadmixture of a film-forming substance selected from the group consistingof polyvinyl alcohol, sodium carboxymethylcellulose,hydroxyethylcellulose and combinations thereof wherein the film-formingsubstance is present in concentrations of 60-95% of the amount of thesolids in the coating, said coating having a thickness within the rangeof 5 μm to 200 μm and said coating confers stability to the activeingredient against oxidation or humidity or both, and said coatingenabling the release of the active substance in all parts of thegastrointestinal tract, regardless of the environmental pH value. 14.The composition according to claim 13 wherein the coating comprises afilm-forming substance which is polyvinyl alcohol.
 15. The compositionaccording to claim 13 wherein the coating comprises a film-formingsubstance which is sodium carboxymethylcellulose.
 16. The compositionaccording to claim 13 wherein the coating comprises a film-formingsubstance which is hydroxyethylcellulose.
 17. The composition accordingto claim 13 wherein the coating further comprises a pharmaceuticalexcipient selected from the group consisting of a buffering agent, analkalizing agent and a surface active agent.
 18. The compositionaccording to claim 13 wherein the coating further comprises apharmaceutical excipient selected from the group consisting of aplasticizer, viscosity-increasing agent of a coating dispersion, filler,lubricant and colorant.
 19. The composition according to claim 13wherein the composition has a water content less than 5 weight percent,based on the total weight of the composition.
 20. A compositioncomprising at least one particle enclosed in a coating, wherein saidparticle comprises an active ingredient which is a HMG-CoA reductaseinhibitor, said active ingredient being susceptible to degradation uponexposure to oxidation or humidity or both, and a coating, wherein saidcoating comprises (a) a film-forming substance selected from the groupconsisting of polyvinyl alcohol, sodium carboxymethylcellulose,hydroxyethylcellulose and combinations thereof and (b) at least onepharmaceutical excipient selected from the group consisting of abuffering agent, an alkalizing agent and a surface active agent whereinthe film-forming substance is present in concentrations of 60-95% of theamount of the solids in the coating, said coating having a thicknesswithin the range of 5 μm to 200 μm and said coating confers stability tothe active ingredient against oxidation or humidity or both, and saidcoating enabling the release of the active substance in all parts of thegastrointestinal tract, regardless of the environmental pH value.